Swift 5.6 cheatsheet
Constants
let myInt = 5
let myString = "Five"
Variables
var myInt = 5
myInt = myInt + 5
Type annotations
let myInt: Int = 5
let myString: String = "Five"
If statement
if 5 > 3 {
print("5 is more than 3")
} else {
print("5 is not more than 3")
}
// Output: "5 is more than 3"
Optionals
let myInt: Int? = 5
if let myInt = myInt {
print("myInt is \(myInt)")
}
// Output: "myInt is 5"
Enum
enum Direction {
case north, south, east, west
}
var direction = Direction.north
Switch statement
switch direction {
case .north:
print("Going north!")
case .south:
print("Going south...")
default:
print("Going east or west.")
}
// Output: "Going north!"
Declaring a function
func square(x: Int) -> Int {
let squaredValue = x * x
return squaredValue
}
Calling a function
let squareOf6 = square(x: 6)
print("6^2 is: \(squareOf6)")
// Output: "6^2 is: 36"
Declaring a struct
struct Player {
let name: String
var score: Int
mutating func doubleScore() {
score *= 2
}
}
Instantiating a struct
var sam = Player(name: "Sam", score: 5)
sam.doubleScore()
print("\(sam.name)'s score: \(sam.score)")
// Output: "Sam's score: 10"
Array
var myArr = [10, 20]
myArr.append(30)
Loop over array
var sum = 0
for element in myArr {
sum += element
}
print(sum)
// Output: "60"